Which is not larger than a mouse pad.

Tablets need extra space only when replacing the embedded touchpads or trackpoints of laptops.

For someone who uses a desktop or who prefers mice to touchpads, a tablet does not need any extra space, it just replaces the mouse and the mouse pad with the stylus and the tablet.

There are big tablets too, but for replacing a mouse and for simple drawings a small tablet like Wacom Intuos S is perfect.